This one is called Murphy's Laws of Combat.
"If the enemy is in range, so are you."
"Incoming fire has the right of way: a. Friendly fire is not really all that friendly: b. Friendly fire is the most accurate fire, due to their knowledge of your location and maneuvers."
"Don't look conspicuous, it draws fire. Like wearing a white hat to a paint ball range!"
"There is always a way."
"The easy way is always mined."
"Try to look unimportant, they may be low on ammo."
"Professionals are predictable, it's the amateurs that are dangerous."
"The enemy invariably attacks on two occasions: a. When you're ready for them: b. When you're not ready for them."
"Teamwork is essential, it gives them someone else to shoot at."
"If you can't remember, the claymore is pointed at you."
"The enemy diversion you have been ignoring will be the main attack."
"A 'sucking chest wound' is nature's way of telling you to slow down."
"If your attack is going well, you have walked into an ambush."
"Never draw fire, it irritates everyone around you."
"Anything you do can get you shot, including nothing."
"Make it tough enough for the enemy to get in and you won't be able to get out."
"Never share a foxhole with anyone braver than yourself."
"If you are short of everything but the enemy, you are in a combat zone."
"When you have secured an area, don't forget to tell the enemy."
"Never forget that your weapon is made by the lowest bidder, and potentially designed by me. That should be your biggest source of comfort."